1 /*- 2 * Copyright (c) 2010 Isilon Systems, Inc. 3 * Copyright (c) 2010 iX Systems, Inc. 4 * Copyright (c) 2010 Panasas, Inc. 5 * Copyright (c) 2013-2016 Mellanox Technologies, Ltd. 6 * Copyright (c) 2015 François Tigeot 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice unmodified, this list of conditions, and the following 14 * disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 * 30 * $FreeBSD: releng/12.2/sys/compat/linuxkpi/common/include/linux/compiler.h 364671 2020-08-24 12:59:55Z manu $ 31 */ 32 #ifndef _LINUX_COMPILER_H_ 33 #define _LINUX_COMPILER_H_ 34 35 #define likely(x) __builtin_expect(!!(x), 1) 36 #define unlikely(x) __builtin_expect(!!(x), 0) 37 #define barrier() __asm__ __volatile__("": : :"memory") 38 #define ACCESS_ONCE(x) (*(volatile __typeof(x) *)&(x)) 39 #define WRITE_ONCE(x,v) do { \ 40 barrier(); \ 41 ACCESS_ONCE(x) = (v); \ 42 barrier(); \ 43 } while (0) 44 45 #define READ_ONCE(x) ({ \ 46 __typeof(x) __var = ({ \ 47 barrier(); \ 48 ACCESS_ONCE(x); \ 49 }); \ 50 barrier(); \ 51 __var; \ 52 }) 53 54 #endif /* _LINUX_COMPILER_H_ */ 55